Thermal barrier potential of a tandem mirror

Journal Article · Mon Dec 01 04:00:00 EST 1986 · Phys. Fluids; (United States)

DOI:https://doi.org/10.1063/1.865758· OSTI ID:6980019

Katanuma, I; Kiwamoto, Y; Ishii, K; Miyoshi, S

The relation between the electrostatic potential and the low energy electron density under electron cyclotron resonance heating (ECRH) in the thermal barrier of a tandem mirror is investigated analytically and numerically. The distribution function of mirror trapped electrons at low energy is found to stretch out in the perpendicular direction to the magnetic field and to be well approximated by a bi-Maxwellian (T/sub perpendicular/greater than or equal toT/sub parallel/) rather than by a Maxwellian. Under this approximation it is found analytically that the conventionally used Boltzmann formula derived from the full Maxwellian plasma for the barrier depth is modified to another expression including the ratio between T/sub perpendicular/ and T/sub e/ (central cell electron temperature). The bounce-averaged Fokker--Planck simulations show that T/sub perpendicular//T/sub e/ itself is a function of the potential depth and that the conventional formula is modified to q(phi/sub b/-phi/sub e/) = T/sub e/ ln(..cap alpha..n/sub c//n/sub b/) with ..cap alpha.. = 1.5--1.8 depending on ECRH power. This expression agrees well with experimental results on GAMMA 10 (Phys. Rev. Lett. 55, 939 (1985)).

• Research Organization: Plasma Research Center, University of Tsukuba, Ibaraki 305, Japan
• OSTI ID: 6980019
• Journal Information: Phys. Fluids; (United States), Journal Name: Phys. Fluids; (United States) Vol. 29:12; ISSN PFLDA
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700101* -- Fusion Energy-- Plasma Research-- Confinement
Heating
& Production
ANALYTICAL SOLUTION
BOLTZMANN EQUATION
BOLTZMANN STATISTICS
CONFINEMENT
COULOMB FIELD
DIFFERENTIAL EQUATIONS
DISTRIBUTION FUNCTIONS
ECR HEATING
ELECTRIC FIELDS
ELECTRON DENSITY
EQUATIONS
FUNCTIONS
HEATING
HIGH-FREQUENCY HEATING
MAGNETIC MIRRORS
NUMERICAL SOLUTION
OPEN PLASMA DEVICES
PARTIAL DIFFERENTIAL EQUATIONS
PLASMA
PLASMA CONFINEMENT
PLASMA HEATING
POTENTIALS
SCALING LAWS
TANDEM MIRRORS
THERMAL BARRIERS
THERMONUCLEAR DEVICES
TRAPPING